1. Field of the Invention
The present invention relates a multi-channel output device for a multimedia device, and more particularly, to a multi-channel output device capable of cutting cost, shrinking chip size, and reducing power consumption.
2. Description of the Prior Art
As a significant progress has been made in multimedia technology, an audio output technology has evolved from mono to stereo or surrounding sound, to provide more entertainment for people. However, the multi-channel output cause more resource consumption. As a result, cost reduction of the multi-channel output has been a main goal in the industry.
Take stereo for example, please refer to FIG. 1, which is a schematic diagram of a stereo output structure 10. The stereo output structure 10 includes amplifiers 100, 102 and speakers 104, 106. The amplifiers 100, 102 are respectively driven by voltage sources VDD1, VDD2 and −VSS, and used for amplifying stereo signals IN_R, IN_L to generate amplifying results OUT_R, OUT_L for the speakers 104, 106. The voltage sources VDD1, VDD2 and −VSS are provided by a power supply (not shown in FIG. 1), such as a charge pump. The stereo signals IN_R, IN_L are, respectively, left-channel signal and right-channel signal output by an audio processor (not shown in FIG. 1).
Thus, as shown in FIG. 1, to correctly process the stereo signals IN_R, IN_L, the stereo output structure 10 needs to amplify the stereo signals IN_R, IN_L through the amplifiers 100, 102, respectively, to play correct contents of the left and right channels. In other words, for the purpose of stereo, the stereo output structure 10 needs two amplifiers 100, 102, which causes cost increase, larger chip size, and more power consumption. Moreover, such issue will get severer as the number of channels increases (e.g. 4 channels, 5.1 channels, etc.). Thus, the stereo output structure in the prior art needs to be improved.